MONTPELIER — The good news is the quality of Montpelier’s water supply is excellent. That’s according to the latest water quality report from the Vermont Department of Environmental Conservation. There’s just one snag.

Because of a plan put in place more than a decade ago, several Berlin customers on the Montpelier system, including the Berlin Volunteer Fire Department, still receive untreated water. And that, says the state, is a no-no and could be costly.

“The brief history in a nutshell is that the city’s water comes from Berlin Pond and the transmission goes down the hill into Montpelier. We have a couple of users in Berlin who, through a longstanding arrangement, have been receiving raw water all along, but it’s a situation that needs to be addressed,” said Tim Raymond, operations section manager for the state drinking water and groundwater protection division.

“We’ve kind of gone back and forth with the state around this,” said Todd Law, chief of the city’s Public Works Department, who said the initial recipients of the untreated water were using it for agricultural purposes. “But we’re hoping that we’re going to have a solution soon.”

Law said those users don’t have any complaints for the time being.

The best solution, according to Law, and the one most easily accomplished, is to move the three remaining raw water users to the Berlin water supply when it comes into being.

According to Law, the city has worked with the residents receiving the untreated water and has gone so far as to start drawing up plans to create an expensive mini treatment plant that would serve the remaining customers. Law said the fire department uses the water only to fill its tankers and another customer has already dug a well.

“Right now, the users have their own filters and ultraviolet lights to treat the water, and everything has been satisfactory,” he added. That said, Law was dismayed when it looked as though it might cost up to $100,000 to create a system that would serve less than a handful of customers.

The state has given the city until August 2014 to set things right with its remaining raw water customers.

According to the compliance schedule, Montpelier must “either provide for filtration and disinfection to those service connections currently being served untreated water ... or physically disconnect those service connections from the raw water transmission lines.”

“Montpelier has very high-quality water,” Raymond said. “So it’s just a little bit of a black eye.”

In the meantime, Law said he’ll move forward to have a plan in place to address the problem.

“We’ve been in the process of getting something ready,” he said. “We’d be happy to turn these customers over to Berlin.”